LTI: Carbon Monoxide (CO) poisoning during Oxy-Acetylene brazing

The incident occurred when the crew member was involved in repairing a broken valve, part of the Freon pipe system for refrigeration. 

While brazing the gas return isolation valve, the crew member felt unwell, but continued the job. 

The task was completed after one hour and then the crew member felt breathing difficulties, was coughing and experienced chest pains.

After a coffee break, the crew member sought medical assistance on board. Medical assessment showed he had a low oxygen saturation level. 

A medevac was activated due to possible respiratory distress or even heart problems.

• The method statement for the repair was to use oxy-acetylene brazing and Tungsten Inert Gas (TIG ) welding methods.
  
  
• All safety controls such as Hot Work PTW, Risk Assessment, Toolbox Talk were in place for the job.

• The crew member did not wear a face mask during the welding job. The company’s procedures did not require the wearing of a face mask for this gas welding, although the wearing of a face mask was identified as a control measure in the risk assessment.
  
  
• The risk assessment for the job was incomplete:
  
  
  • Wearing of a face mask was indicated in the PTW as an “additional protection only”.
    
    
  • The need for a portable exhaust ventilation system was not identified for this working area.
    
    
  • The risks and hazards associated with TIG welding were not identified.
    
    
• The crew member did not take regular breaks during the task as indicated in the Risk Assessment, and kept on working when he felt ill rather than stopping and reconsidering.
  
  
• The crew member was unaware of the risks and hazards associated with TIG welding. The molten metal gives off molecules of metal and ozone which are harmful to respiration.